The present invention is directed to a surgical tool of the type employed for nibbling or shearing away small chips of bone during surgical procedures. Many specialized tools, such as ronguers, have been devised for this purpose.
Typically these tools have a pair of opposed surfaces, at least one of which is sharpened, which are moved toward each other by manually squeezing a pair of plier-like handles to grip and cut away that portion of a bone engaged between the opposed surfaces. See, for example, U.S. Pat. Nos. 1,040,523 to DeVilbiss and 4,201,213to Townsend.
While many specialized instruments have been developed for this purpose, nearly all prior art instruments of this type known to me have one or more of the following drawbacks.
One of the most common problems encountered with prior art instruments is the fact that the cutting edge of the device is formed integrally upon one of the two shearing members, thus requiring specialized tools or techniques when it is necessary to resharpen the cutting edge. In the instrument of the present application, the cutting edge is formed on one end of a short length of metal tubing. This edge may be readily resharpened by chucking the cutting element in a rotary tool; however, this form of cutting element is so inexpensive it may be disposable after a single usage.
As with any surgical instrument, the capability of being thoroughly cleaned and sterilized is paramount. Because instruments of this type are made up of several moving parts, ease of assembly and disassembly is an important consideration which has not always received sufficient attention in prior art devices. The instrument to the present invention can be readily assembled and disassembled without the use of tools.
Typically, such instruments are of generally pistol shape with one of the opposed gripping surfaces at the end of the "barrel" and the other gripping surface provided by a generally radial recess in a rod which slidably projects from the end of the barrel. Depending upon the particular surgical procedure, the surgeon will select a ronguer called a "up-cutting" or "down-cutting" ronguer. An up-cutting ronguer finds the bone receiving recess in the cutting elements facing upwardly when the pistol-shaped instrument is held in its normal position; a down-cutting ronguer finds the recess on the bottom side of the cutting element. The instrument of the present invention enables the recess to be selectively located in an up-cutting, down-cutting or either side-cutting orientation; whereas in the prior art constructions, a single instrument usually provides only the capability of one type of cutting.
Further, the instrument of the present invention includes a relatively simple linkage actuating mechanism which provides a substantial mechanical advantage and also presents the capability of substituting or replacing the stationary grip portion of the handle to suit the surgeon.